What is Jenkins?

Jenkins is an open-source automation server. Jenkins manages and controls software delivery processes throughout the entire lifecycle, including build, document, test, package, stage, deployment, static code analysis, and much more.

You can set up Jenkins to watch for any code changes in places like GitHub, Bitbucket or GitLab and automatically do a build a with tool like Maven. You can utilize container technology such as Docker and Kubernetes, initiate tests and then take actions like rolling back or rolling forward in production.

Why Jenkins?

Jenkins is one of the top DevOps tools because it is free, open-source, and modular, and can integrate with pretty much every other DevOps tool out there. There are over a thousand plugins that you can use to extend Jenkins’ capabilities and make it more user-specific. All of these plugins and extensions are developed in Java. This means that Jenkins can also be installed on any operating system that runs on Java.

What Is Jenkins Used For?

Jenkins software’s popularity stems from its ability to track and monitor repetitive activities that emerge throughout a project’s development. For example, if your team is working on a project, Jenkins will continually test your builds and alert you to any mistakes early in the process. it’s top use cases include;

1- Deploying code into production

2- Enabling task automation

3- Reducing the time it takes to review a code

4- Enhancing coding efficiency

5- Increasing code coverage

What Is a Jenkins Pipeline?

Jenkins Pipeline is a collection of jobs or events that brings the software from version control into the hands of the end users by using automation tools. It is used to incorporate continuous delivery in our software development workflow. A pipeline has an extensible automation server for creating simple or even complex delivery pipelines “as code”, via DSL.

Each Jenkins pipeline has a definition written in a text-based Jenkinsfile which development teams can commit to their source control repository. This textual approach is the core of the pipeline as a code method that treats the CD pipeline as an integral part of the application code. Like other code, team members can version and review it.

• Continuous integration server (Jenkins)

• Source control software (GIT)

• Build tool (Maven)

• Automation testing framework (Appium, Selenium)

What is Continuous Delivery Pipelines?

It contains a group of states called build, deploy, test and release. These events are interlinked with each other. Every state has its events, which work in a sequence called a continuous delivery pipeline.

How Does Jenkins Work?

Each time a developer publishes a commit to the source code repository, Jenkins triggers a build. Typically, the commits are posted to a development branch.

The build steps include testing the code, and ensuring the build does not break. If any error occurs, Jenkins notifies the developer to act accordingly. If all tests pass, the Pipeline proceeds to the integration steps.

Integration takes longer and requires testing the code against multiple system configurations. Jenkins performs parallel integration tests on different nodes, reducing the time needed to try and integrate code.

Further down the Pipeline, Jenkins automates user acceptance testing which is a requirement before deployment. If all tests pass, the code merges into the main branch, making the code available to the users.

In this video, we go over what is Jenkins, and how we can install Jenkins and create CI/CD Pipelines.

Let’s deep dive into learning Jenkins in detail.